A species of coin fraud has arisen in which the miscreant drills a hole through a coin of the type accepted by a coin-operated device, such as a coin telephone instrument, and attaches a flexible cord or string, such as monofilament fishing line, to the coin by threading the string through the drilled hole and knotting the end to tether the coin. The coin is then deposited in the coin slot, the tethered string allowing it to fall through the coin chute of the coin telephone instrument where it triggers the deposited coin registration switch if it is recognized as a genuine coin, or is rejected to the coin return bucket if determined to be counterfeit. If the coin is recognized as valid, the coin will be held in the escrow hopper where it is stopped by a trap door until a call is placed and has been answered. The fraudulent user, however, hangs up before answer is received. In response to hangup, the telephone instrument then activates a coin return operation. The trap door opens in sequence just after a coin steering vane moves to the coin refund position. The fraudulent user allows the coin to pass through the trap door, but suspends it just below the trap door. This allows the trap door to close but the suspended coin keeps the telephone instrument's coin steering vane biased to allow coins to enter the coin return chute. The closing of the trap door allows the telephone instrument to be reset for a new call, which the fraudulent user now places. However, because the suspended coin has fouled the apparatus, all deposited coins will be returned to the miscreant at the end of the call. It would be extremely advantageous to be able to frustrate such fraudulent usage.